Exhaust gas purifying device for engines

Abstract

An engine is disposed with a crankshaft axially oriented in the longitudinal direction of the vehicle body. A camshaft and an exhaust port in a cylinder head are disposed parallel to the crankshaft. The exhaust port is open at the front surface of the cylinder head, and discharges exhaust gases through an exhaust pipe. Hoses extend from a radiator in front of the engine to the front surface of the engine. A valve case is disposed on a left side of a cylinder block in the vicinity of the exhaust port to which the exhaust pipe is connected, and is connected to an air cleaner behind the engine by a substantially straight secondary air pipe.

What is claimed is:  
     
         1 . An exhaust gas purifying device for a four-cycle engine having a secondary air supply passage for supplying secondary air to an exhaust port and a valve for opening and closing the secondary air supply passage with exhaust pulsations, comprising: 
 said exhaust port is disposed parallel to a camshaft as viewed in a plan view of the engine, and said valve is disposed on a side of the engine which is perpendicular to said camshaft.    
     
     
         2 . The exhaust gas purifying device according to  claim 1 , wherein said valve is disposed on either a left or right side of a vehicle body, and a pipe for supplying the secondary air is connected between the valve and an air cleaner disposed behind the engine.  
     
     
         3 . The exhaust gas purifying device according to  claim 1 , wherein the secondary air supply passage includes a substantially vertical hole and a substantially horizontal hole disposed in a cylinder block for communicating with the exhaust port.  
     
     
         4 . The exhaust gas purifying device according to  claim 3 , wherein the secondary air supply passage includes a substantially vertical hole and a substantially horizontal hole disposed in a cylinder head for communicating with the exhaust port.  
     
     
         5 . The exhaust gas purifying device according to  claim 4 , wherein said cylinder head is mounted on said cylinder block and said substantially vertical hole and the substantially horizontal hole disposed in the cylinder block and the cylinder head are in communication with each other and with the exhaust port.  
     
     
         6 . The exhaust gas purifying device according to  claim 5 , and further including a secondary air supply conduit operatively connected to an air cleaner and said substantially vertical hole and the substantially horizontal hole disposed in the cylinder block and the cylinder head for communicating air to the exhaust port.  
     
     
         7 . The exhaust gas purifying device according to  claim 5 , wherein said valve is a reed valve operatively positioned relative to the substantially vertical hole and a substantially horizontal hole disposed in the cylinder block and the cylinder head for selectively permitting communication between the secondary air supply conduit and the exhaust port.  
     
     
         8 . The exhaust gas purifying device according to  claim 7 , wherein said reed valve is disposed relative to the substantially horizontal hole disposed in the cylinder block.  
     
     
         9 . An exhaust gas purifying device for a four-cycle engine comprising: 
 an exhaust port;    a secondary air supply passage for supplying secondary air to the exhaust port; and    a valve for selectively opening and closing the secondary air supply passage in response to exhaust pulsations;    wherein said exhaust port is disposed parallel to a camshaft as viewed in a plan view of the engine and said valve is disposed on a side of the engine which is perpendicular to said camshaft.    
     
     
         10 . The exhaust gas purifying device according to  claim 9 , wherein said valve is disposed on either a left or right side of a vehicle body, and a pipe for supplying the secondary air is connected between the valve and an air cleaner disposed behind the engine.  
     
     
         11 . The exhaust gas purifying device according to  claim 9 , wherein the secondary air supply passage includes a substantially vertical hole and a substantially horizontal hole disposed in a cylinder block for communicating with the exhaust port.  
     
     
         12 . The exhaust gas purifying device according to  claim 11 , wherein the secondary air supply passage includes a substantially vertical hole and a substantially horizontal hole disposed in a cylinder head for communicating with the exhaust port.  
     
     
         13 . The exhaust gas purifying device according to  claim 12 , wherein said cylinder head is mounted on said cylinder block and said substantially vertical hole and the substantially horizontal hole disposed in the cylinder block and the cylinder head are in communication with each other and with the exhaust port.  
     
     
         14 . The exhaust gas purifying device according to  claim 13 , and further including a secondary air supply conduit operatively connected to an air cleaner and said substantially vertical hole and the substantially horizontal hole disposed in the cylinder block and the cylinder head for communicating air to the exhaust port.  
     
     
         15 . The exhaust gas purifying device according to  claim 13 , wherein said valve is a reed valve operatively positioned relative to the substantially vertical hole and a substantially horizontal hole disposed in the cylinder block and the cylinder head for selectively permitting communication between the secondary air supply conduit and the exhaust port.  
     
     
         16 . The exhaust gas purifying device according to  claim 15 , wherein said reed valve is disposed relative to the substantially horizontal hole disposed in the cylinder block.